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Abstract:

A gas generator assembly includes a propellant chamber housing an amine
based propellant. A reaction chamber is coupled with the propellant
chamber. The reaction chamber includes a reaction chamber housing, and a
porous reaction matrix within the reaction chamber housing. The reaction
matrix includes a catalyzing agent, and the catalyzing agent is
configured to non-combustibly catalyze the amine based propellant into
one or more pressurized gases. An injector is in communication with the
propellant chamber. The injector is configured to deliver the amine based
propellant to the porous reaction matrix. A discharge nozzle is coupled
with the reaction chamber and is configured to accelerate and discharge
the one or more pressurized gases. In one example, the gas generator is
coupled with one or more of an impulse turbine assembly and an electric
generator to form a micro power unit.

Claims:

1. A gas generator assembly comprising: a pressure generator; a
propellant chamber coupled with the pressure generator, the propellant
chamber houses a fluid amine based propellant; a reaction chamber coupled
with the propellant chamber, the reaction chamber includes: a reaction
chamber housing, a porous reaction matrix within the reaction chamber
housing, the reaction matrix includes a catalyzing agent, and the
catalyzing agent is configured to non-combustibly catalyze the amine
based propellant into one or more pressurized gases, and an injector in
communication with the propellant chamber, the injector is configured to
deliver the amine based propellant to the porous reaction matrix; and a
discharge nozzle coupled with the reaction chamber, the discharge nozzle
is configured to accelerate and discharge the one or more pressurized
gases.

2. The gas generator assembly of claim 1, wherein the amine based
propellant has a specific gravity greater than or equal to around 1.6.

3. The gas generator assembly of claim 1, wherein the discharge nozzle is
a rocket discharge nozzle, and the rocket discharge nozzle is configured
to accelerate the one or more pressurized gases to supersonic velocity of
around 5000 to 7000 feet per second.

4. The gas generator assembly of claim 1, wherein the propellant chamber
and the reaction chamber are a closed system, and the porous reaction
matrix and the amine based propellant are isolated from ambient air while
the porous reaction matrix non-combustibly catalyzes the amine based
propellant.

5. The gas generator assembly of claim 1, wherein the porous reaction
matrix includes aluminum oxide and the catalyzing agent includes platinum
particles within the porous reaction matrix.

8. The gas generator assembly of claim 7, wherein the preheating
substrate includes a hypergolic substance, and the hypergolic substance
is configured to react with the amine based propellant to preheat the
porous reaction matrix.

9. The gas generator assembly of claim 7 comprising: a propellant
throttle coupled between the propellant chamber and the reaction chamber;
and a temperature sensor coupled with the porous reaction matrix, wherein
propellant throttle is configured to meter a flow of the amine based
propellant to the porous reaction matrix according to measurements of the
temperature sensor.

10. A system comprising a micro power unit including: a propellant
chamber housing a liquid propellant; a reaction chamber coupled with the
propellant chamber, the reaction chamber includes: a porous reaction
matrix, the reaction matrix includes a catalyzing agent, and the
catalyzing agent is configured to non-combustibly catalyze the liquid
propellant into one or more pressurized gases, and an injector configured
to deliver the liquid propellant to the porous reaction matrix; a
discharge nozzle coupled with the reaction chamber, the discharge nozzle
is configured to accelerate and discharge the one or more pressurized
gases; and an impulse turbine including one or more tangential cups,
wherein the discharge nozzle is configured to discharge the one or more
pressurized gases into the one or more tangential cups and rotate the
impulse turbine.

11. The system of claim 10, wherein the impulse turbine is coupled with
an alternator.

12. The system of claim 10, wherein the one or more tangential cups are
at a radius of around 0.5 inches from an impulse turbine axis of
rotation.

13. The system of claim 10, wherein the discharge nozzle is directed at a
right angle relative to an impulse turbine axis of rotation, and the
discharge nozzle is directed coincident to the one or more tangential
cups.

14. A method for using a gas generator comprising: delivering an amine
based propellant to a reaction chamber; directing the amine based
propellant through a porous reaction matrix, the porous reaction matrix
includes a catalyzing agent; non-combustibly catalyzing the amine based
propellant into one or more pressurized gases with the porous reaction
matrix; and accelerating and discharging the one or more pressurized
gases through a discharge nozzle.

15. The method of claim 14, wherein accelerating and discharging the one
or more pressurized gases includes accelerating the one or more
pressurized gases to supersonic velocity.

16. The method of claim 14, wherein non-combustibly catalyzing the amine
based propellant includes non-combustible catalyzing in a closed system,
wherein the porous reaction matrix and the amine based propellant are
isolated from ambient air.

17. The method of claim 14 comprising preheating the porous reaction
matrix with a preheating substrate.

18. The method of claim 17, wherein preheating includes: delivering a
preheating pulse of the amine based propellant to the preheating
substrate including a hypergolic substance, and reacting the amine based
propellant with the hypergolic substance to produce heat.

19. The method of claim 17 comprising: measuring the temperature of the
porous reaction matrix against a temperature threshold; and delivering a
catalyzing stream of the amine based propellant to the porous reaction
matrix if the temperature meets or exceeds the temperature threshold.

20. The method of claim 14, wherein accelerating and discharging the one
or more pressurized gases includes discharging the one or more
pressurized gases against an impulse turbine.

21. The method of claim 20 comprising throttling power generated from the
impulse turbine through throttling delivery of the amine based propellant
to the reaction chamber.

22. The method of claim 14, wherein accelerating and discharging the one
or more pressurized gases includes discharging the one or more
pressurized gases including oxygen generated through non-combustibly
catalyzing through a rocket motor, and the rocket motor includes a solid
fuel configured for combustion with the oxygen.

23. An unmanned aerial vehicle (UAV) comprising: a flight control system
including a receiver; an electric generator; a micro power unit of claim
10 coupled with the electric generator, the micro power unit is
configured to drive the electric generator, wherein electricity generated
by the electric generator is provided to the flight control system.

24. The UAV of claim 23 comprising an electric motor, wherein the
electricity generated by the electric generator is provided to the
electric motor to turn a propeller.

25. The UAV of claim 23 comprising a pitch-controlled propeller driven by
the micro-power unit wherein a pitch of the propeller is controllable.

26. The UAV of claim 23, wherein the micro power unit has an initial
weight and a post operation weight, wherein: the micro power unit is at
the initial weight prior to catalyzing the liquid propellant, and the
micro power unit is at the post operation weight after the liquid
propellant is catalyzed, wherein the post operation weight is less than
around 30 percent of the of initial weight, and the micro power unit and
the UAV decrease in weight throughout catalyzing of the liquid
propellant.

27. A battery charger for a man-portable device comprising: an electric
generator; a micro power unit of claim 10 coupled with the electric
generator, the micro power unit is configured to drive the electric
generator; and wherein electricity generated by the electric generator is
provided through a regulator for charging a battery.

Description:

TECHNICAL FIELD

[0001] Embodiments pertain to closed system gas generators operating
without ambient air and micro power units and unmanned air vehicles using
the same.

BACKGROUND

[0002] Small scale unmanned air vehicles (UAVs) and other small scale
vehicles and field operated devices often use batteries for electrical
and electro-mechanical operation. Batteries are often heavy and add
significant weight to these devices and UAVs. In the case of UAVs added
battery weight diminishes performance and flight time. Additionally,
batteries often take up significant amounts of space within devices that
would otherwise be devoted to miniaturizing devices or adding additional
functionality. In UAVs a larger fuselage is required to contain the
batteries needed for operation. Further, a larger propulsion source
(e.g., a motor and propeller) and wings with attendant weight increases
for both may be needed to ensure a battery operated UAV has the
performance and lifespan required.

[0003] Further, in at least some circumstances it is often necessary to
store battery operated devices and UAVs for significant periods (e.g.,
months, years and the like) before operation is desired. Batteries
frequently lose all or part of their charge when stored. Devices and UAVs
including aged batteries may thereby have no or limited performance and
correspondingly have limited reliability in the field. In some
circumstances, for instance during deployment and when remote from a
source of resupply, it may be extremely difficult to find a replacement
battery or recharge a battery without special equipment that may not be
available or portable.

SUMMARY

[0004] In accordance with some embodiments, the non-combusting gas
generator described herein provides an assembly configured to generate a
source of exhaust gas for use in a micro power unit. The non-combusting
gas generator includes a propellant chamber housing a dense
non-combustible propellant. The propellant is introduced to a reaction
chamber including a porous reaction matrix having a catalyst suspended in
the porous reaction matrix. The catalyst catalyzes the propellant within
the reaction matrix and generates exhaust gases for use by one or more
mechanical and electrical systems. Combining the gas generator with power
generation systems including, but not limited to, turbine assemblies and
electric generators forms a micro power unit configured to generate
significant power as a closed compact system.

[0005] The gas generator assembly introduces and consumes the propellant
(e.g., an amine based propellant, such as hydroxyl ammonium nitrate)
within a closed system. The gas generator assembly does not require
ambient air mixed with the propellant to catalyze or react the propellant
and produce the exhaust gases. Stated another way, the gas generator
assembly does not combust the propellant (e.g., with ambient air).
Instead, the propellant is catalyzed within a closed system and the
exhaust gases are reliably produced in substantially any environment
(e.g., vacuum, high and low oxygen environments and the like).

[0006] Further, the propellant used with the gas generator assembly is a
stable non-combustible propellant. In one example, the propellant is an
amine based propellant, such as a hydroxyl ammonium nitrate. As described
herein, the amine based propellant is catalyzed within the porous
reaction matrix including a catalyst to produce exhaust gases. The
non-combusting propellant is not combustible by itself and is
correspondingly stable. Accordingly, the propellant may be stored for
months or years with no significant performance degradation.
Additionally, because the propellant is non-combustible it is a minimal
hazard to transport and store relative to other combustible propellants.
Further still, in the case of the amine based propellant described herein
the propellant is dense (e.g., with a specific gravity greater than
around 1.6) and a small amount of the propellant generates a significant
amount of exhaust gas. The gas generator assembly including the amine
based propellant thereby has a small form factor. The gas generator
assembly is readily incorporated as a compact component of devices
including miniaturized UAVs and other field equipment while still
delivering significant power to the devices over a specified operational
lifespan.

[0007] Moreover, the exhaust gas generated by the non-combusting gas
generator is directed through a discharge nozzle for use by one or more
components. In one example, the exhaust gas is accelerated to supersonic
velocity (e.g., 5000 to 7000 feet per second) and impinges against one or
more tangential cups of an impulse turbine. The impulse turbine relies
heavily on the velocity of the exhaust gas to rotate and correspondingly
generate power (as opposed to volumetric flow rate used in axial
turbines). The discharge nozzle minimizes the volumetric flow rate and
thereby conserves the propellant for extended performance of the gas
generator assembly and operation of the impulse turbine. As described
herein the impulse turbine assembly is coupled with one or more of an
electric generator to generate electric power or a reduction drive
coupled with a propulsion device (e.g., a propeller) of a miniaturized
UAV. Furthermore, during operation of the gas generator the propellant is
gradually consumed and exhausted from the UAV. The weight of the UAV
gradually decreases over its operation and thereby allows the gas
generator and the other components of the micro power unit to efficiently
power the lighter weight UAV.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more complete understanding of the present subject matter may be
derived by referring to the detailed description and claims when
considered in connection with the following illustrative Figures. In the
following Figures, like reference numbers refer to similar elements and
steps throughout the Figures.

[0009] FIG. 1 is a schematic view of one example of a non-combusting gas
generator.

[0010] FIG. 2 is a schematic view of one example of a reaction chamber for
use with the non-combusting gas generator shown in FIG. 1.

[0011] FIG. 3A is a front view of one example of a porous reaction matrix
for use with the reaction chamber shown in FIG. 2.

[0012] FIG. 3B is a side view of one example of the porous reaction matrix
shown in FIG. 3A.

[0013] FIG. 4 is a schematic view of an example propellant chamber and an
example pressure generator coupled with the propellant chamber.

[0014]FIG. 5 is a schematic view of the gas generator of FIG. 1 coupled
with one example of an impulse turbine within a turbine housing.

[0015] FIG. 6 is a top view of the impulse turbine and the turbine housing
of FIG. 5.

[0016] FIG. 7 is a schematic view of the gas generator of FIG. 1 coupled
with an electric generator.

[0017]FIG. 8 is a perspective view of one example of a miniaturized
unmanned air vehicle including the non-combusting gas generator of FIG. 1
and the electric generator of FIG. 6.

[0018] FIG. 9 is a side/perspective view of one example of a battery
charger including the non-combusting gas generator of FIG. 1 and the
electric generator of FIG. 7.

[0019] FIG. 10 is a schematic diagram of one example of a rocket motor
coupled with the non-combusting gas generator of FIG. 1.

[0020] FIG. 11 is a block diagram showing one example of a method for
using a gas generator.

[0021] Elements and steps in the Figures are illustrated for simplicity
and clarity and have not necessarily been rendered according to any
particular sequence. For example, steps that may be performed
concurrently or in different order are illustrated in the Figures to help
to improve understanding of examples of the present subject matter.

DESCRIPTION OF THE DRAWINGS

[0022] In the following detailed description, reference is made to the
accompanying drawings which form a part hereof, and in which is shown by
way of illustration specific examples in which the subject matter may be
practiced. These examples are described in sufficient detail to enable
those skilled in the art to practice the subject matter, and it is to be
understood that other examples may be utilized and that structural
changes may be made without departing from the scope of the present
subject matter. Therefore, the following detailed description is not to
be taken in a limiting sense, and the scope of the present subject matter
is defined by the appended claims and their equivalents.

[0023] The present subject matter may be described in terms of functional
block components and various processing steps. Such functional blocks may
be realized by any number of techniques, technologies, and methods
configured to perform the specified functions and achieve the various
results. For example, the present subject matter may employ various
materials, actuators, electronics, shape, airflow surfaces, reinforcing
structures, propellants and the like, which may carry out a variety of
functions. In addition, the present subject matter may be practiced in
conjunction with any number of devices, and the systems described are
merely exemplary applications.

[0024] FIG. 1 shows one example of a gas generator assembly 100. As
described in further detail below the gas generator assembly 100
non-combustibly generates exhaust gas, for use in one example within a
micro-power unit. As shown, the gas generator assembly 100 includes a
propellant chamber 102 coupled with a reaction chamber 106. The
propellant chamber 102 includes a propellant, such as an amine based
propellant. In one example, the propellant 104 is a liquid propellant
housed in the propellant chamber 102 configured for delivery through a
propellant passage 114 to the reaction chamber 106. The reaction chamber
106 includes a porous reaction matrix 108 (e.g., a catalyst bed)
configured to receive the propellant 104 from the propellant chamber 102
and catalyze the propellant to produce one or more high temperature
exhaust gases. As shown in FIG. 1, in one example, the reaction chamber
106 includes an injector 110 sized and shaped to couple the reaction
chamber 106 with the propellant passage 114 extending from the propellant
chamber 102. The injector 110 includes, but is not limited to, an
atomizer configured to atomize the liquid propellant 104 delivered
through the propellant passage 114. Atomizing of the propellant 104
sprays the propellant across the reaction chamber 106 and ensures the
propellant is delivered through substantially all of the passages within
the porous reaction matrix 108. The reaction chamber 106 further includes
a discharge nozzle 112 at an opposed end of the reaction chamber 106 from
the injector 110. As will be described in further detail below, the
discharge nozzle 112 is sized and shaped to receive exhaust gases
developed through catalyzation of the propellant 104 within the porous
reaction matrix 108. The discharge nozzle 112 is further configured to
accelerate the exhaust gases from the reaction chamber 106 to high
velocity, for instance, supersonic velocity. The exhaust gases are
delivered through the discharge nozzle 112 to one or more components
including but not limited to a turbine, rocket motor and the like.

[0025] As shown in FIG. 1, the gas generator assembly 100 is a
substantially closed system. The propellant 104 within the propellant
chamber 102 is isolated from the outside environment. Stated another way
the propellant 104, such as an amine based propellant, is not mixed with
any other fuel or gas such as ambient air prior to delivery to the
reaction chamber 106. The propellant 104 including, for instance an amine
based propellant (e.g., hydroxyl ammonium nitrate), is instead delivered
through the propellant passage 114 (for instance, through a check valve
in the propellant passage) and into the reaction chamber 106 where the
amine based propellant by itself reacts with the porous reaction matrix
108 to produce one or more exhaust gases at elevated temperatures and
elevated pressure.

[0026] As will be described in further detail below, the exhaust gases
developed in the reaction chamber 106, for instance, through the
catalyzation of the propellant 104 by the porous reaction matrix 108
provide a high velocity stream of gas through the discharge nozzle 112
capable of operating one or more components against which the discharge
gas impinges (e.g., an impulse turbine assembly within a micro-power
unit). The high velocity stream of gas provided by the discharge nozzle
112 allows the gas generator assembly 100 to operate components such as
impulse turbines with a minimal volumetric flow rate in combination with
a high velocity flow of gas. Because the gas generator assembly 100
relies on the discharge of high velocity of gases through the discharge
nozzle 112 the assembly is miniaturized relative to other assemblies such
as axial power generation assemblies including axial turbines that rely
heavily on volumetric flow rate to generate adequate power. In contrast
to previous systems, the gas generator assembly 100 uses an amine based
propellant 104 having a high specific gravity (e.g., greater than 1.6)
and corresponding high density that is compact relative to other fuels
that require the mixture of a propellant with ambient air. By using a
propellant 104, such as the amine based propellant, by itself without the
addition of any ambient air or other fuels the gas generator assembly 100
is substantially minimized relative to the other power generation
assemblies requiring mixed fuels.

[0027] Referring again to FIG. 1, the catalyzation of the propellant 104
generates hot exhaust gases, for instance, exhaust gases reaching
temperatures of around 1200 degrees Fahrenheit or more. The reaction
chamber 106 as will be described below is constructed with robust
materials to withstand the temperature and pressure of the exhaust gases
generated therein. In one example, the reaction chamber 106 generates one
or more of nitric oxides, nitrous oxides and oxygen. As previously
described, the exhaust gases are discharged through the discharge nozzle
112 at high pressure to generate mechanical power, electricity and the
like for use in miniaturized unmanned air vehicles, rocket motors,
battery chargers, other electrical devices and the like. Stated another
way, the gas generator assembly in combination with for instance a
turbine assembly comprises a micro-power unit configured to generate one
or more of mechanical and electrical power within a compact package.

[0028] FIG. 2 shows one example of the reaction chamber 106. As shown, the
reaction chamber 106 shown in FIG. 2 includes the porous reaction matrix
108 within a reaction chamber body 200. As previously described, the
propellant 104 delivered to the reaction chamber 106 is catalyzed by the
porous reaction matrix 108. Referring to FIG. 2, the porous reaction
matrix 108 is shown with a plurality of matrix passage 202 extending
therethrough. For instance, as shown in FIG. 2, the matrix passages 202
extend from a portion of the reaction chamber 106 adjacent to the chamber
proximal portion 216 to the chamber distal portion 218 (adjacent to the
discharge nozzle 112).

[0029] The porous reaction matrix 108, for instance a catalyst bed, in one
example includes a plurality of linear matrix passages 202 extending
therethrough. In another example, the porous reaction matrix 108 includes
sheets or members of a matrix substrate such as aluminum oxide
(Al2O3). In one example, the matrix passages 202 are formed by
horizontal and vertical plates formed into a grid with the matrix
passages. The catalyst 204 is positioned on the walls of the matrix
passages 202 and is thereby exposed to the propellant 104 as the
propellant is delivered through the porous reaction matrix 108. As shown
in FIG. 2, the catalyst 204 is shown with stippling along each of the
plurality of matrix passages 202. In one example, the catalyst 204
includes but is not limited to platinum (Pt) and the like. The platinum
catalyzes the amine based propellant 104 contained within the propellant
chamber 102. As previously described, the exposure of the catalyst 204 to
the propellant 104 generates one or more exhaust gases at high
temperature and high pressures, for instance, the exhaust gases include
nitrous oxide, nitric oxide, oxygen and the like. In one example, the
catalyst 204 initiates and accelerates the disassociation of the
propellant 104 into the exhaust gases. In another example, the exhaust
gases are generated and have a temperature of around 1200 degrees
Fahrenheit. The reaction chamber body 200 is constructed with materials
that are substantially robust when containing exhaust gases at these
temperatures and high pressures, for instance, pressures greater than 300
to 400 psi. For instance, the reaction chamber body 200 is constructed
with but not limited to metals such as stainless steel, aluminum,
titanium and the like.

[0030] FIG. 2 also shows one example of a preheating assembly 206 coupled
with the reaction chamber 106. In one example, the preheating assembly
206 includes a preheater 208 coupled with the porous reaction matrix 108.
In one example, the preheater 208 includes a porous substrate coupled
over a plurality of the matrix passages 202. As shown in FIG. 2, the
preheater 208 blankets a majority of the matrix passages 202. In another
example, the preheater 208 is coupled over a smaller subset of the matrix
passages 202. In one example, the preheater 208 includes a hypergolic
solid powder contained within a porous pillow such as sandwiched layers
of cellulose containing the hypergolic powder therein. As the propellant
104 is introduced to the reaction chamber 106 the propellant 104 passes
through the porous preheater 208 and reacts with the hypergolic powder
within the preheater 208. The amine based propellant 104 immediately
reacts with the preheater 208 and rapidly generates heat that
correspondingly heats the porous reaction matrix 108. In one example, the
hypergolic composition used with the preheater 208 includes but is not
limited to a mixture of sodium chlorohydrate, cupric oxide (e.g., 0.1 to
1 percent mass), magnesium (e.g., 1 to 10 percent mass). In one example,
trace elements of cupric oxide and magnesium facilitate the reaction
between the preheater 208 and the propellant 104. In yet another example,
the preheater 208 includes lithium borohydride. Where the hypergolic
composition includes lithium borohydride cuprix oxide may be removed from
the composition as the lithium borohydride performs a similar function
within the preheater 208.

[0031] As further shown in FIG. 2, the preheating assembly 206 further
includes, in one example, a temperature sensor 210 coupled with the
porous reaction matrix 108. The temperature sensor 210 is coupled along
an opposed surface of the porous reaction matrix 108. In another example,
the temperature sensor 210 is coupled with the porous reaction matrix 108
at a different location, for instance, within the porous reaction matrix
or along the identical surface of the porous reaction matrix to the
preheater 208. As shown in FIG. 2, the temperature sensor 210 is coupled
with a propellant control valve, for instance, a needle valve 212 through
a control coupling 214. In one example, one or more of the temperature
sensor 210 and the propellant control valve 212 includes a mechanism
(e.g., software, hardwiring, a thermostat, mechanical operator and the
like) configured to operate the propellant control valve 212 according to
the temperature measurement of the temperature sensor 210.

[0032] In one example, the operation of the gas generator assembly 100
includes an initial step where the temperature sensor 210 opens the
propellant control valve 212 a small amount to allow a small pulse of
amine based propellant 104 into the reaction chamber 106. The small pulse
reacts with the preheater 208 to preheat the porous reaction matrix 108.
Upon a determination by the temperature sensor 210 and that a desired
threshold temperature has been reached in the porous reaction matrix the
propellant control valve 212 (e.g., according to the control mechanism)
is fully opened to allow a full stream of the propellant 104 into the
reaction chamber 106 for catalyzing by the now preheated porous reaction
matrix 108. The preheated porous reaction matrix 108 initiates and
accelerates the catalyzation of the the propellant 104 thereby ensuring
the generation of exhaust gases for discharge through the discharge
nozzle 112. In one example, the preheater 208 preheats the porous
reaction matrix 108 and the catalyst 204 to an initiation temperature
configured to initiate and accelerate the breakdown of the propellant 104
(e.g., from around 260 degrees Celsius to 1100 degrees Celsius). In
another example, where the porous reaction matrix 108 and the catalyst
204 are preheated to these temperatures the catalyst is maintained within
the matrix and with cleaning of the gas generator assembly 100 and
recharging with propellant 104 the assembly 100 is readily operated
again. The gas generator assembly 100 may thereby be recycled for
continued repeated use.

[0033] In operation, the amine based propellant 104 is delivered by itself
(e.g., without any other fuel or ambient air) through the atomizer 110
through the porous reaction matrix 108. In one example, as described
above the porous reaction matrix 108 is preheated with the preheating
assembly 206 including, for instance, the preheater 208. The amine based
propellant 104 is a non-combustible propellant and is catalyzed by the
porous reaction matrix 108. Stated another way, because the amine based
propellant 104 is non-combustible mixing with ambient air and other fuels
is not needed as the amine based propellant is configured to react by
itself with the porous reaction matrix 108. The non-combustible
catalyzation of the non-combustible amine based propellant 104 with the
porous reaction matrix 108 makes the gas generator assembly 100 (see FIG.
1) substantially non-hazardous relative to other combustion generator
systems. For instance, the amine based propellant 104 is stable and not
hazardous relative to other combustible fuels and propellants.

[0034] Further, because the gas generator assembly 100 including the
reaction chamber 106 uses an amine based propellant 104 without any other
fuels the amine based propellant provides a substantially dense (relative
to water) propellant that uses only a small amount of propellant per unit
time That is to say, the porous reaction matrix 108 is configured to
catalyze the amine based propellant 104 for a few seconds to over a
minute with a small miniaturized package carrying a correspondingly small
propellant charge in the propellant chamber 102. As described in further
detail below, the porous reaction matrix 108 catalyzes the amine based
propellant 104 to generate a high velocity stream of gas. The exhaust gas
is accelerated through the discharge nozzle 112 and is delivered to
mechanical components configured to utilize the high velocity gas without
requiring a significant volumetric flow as in the case of radial turbines
as opposed to axial turbines and the like that require high volumetric
flow rates. Stated another way, other power generation devices require a
propellant mixed with other fuels and ambient air to generate a large
volumetric flow rate for power generation. The mixture of these fuels
require additional mechanical features, for instance, gas inlets,
compressors and the like. The gas generator assembly 100 described herein
including the porous reaction matrix 108 within the reaction chamber 106
precludes the inclusion of these mechanical features and instead relies
on a single source of propellant such as the propellant 104 (an amine
based propellant) within the reaction chamber 106 to generate a high
velocity stream of exhaust gases with a corresponding low volumetric flow
rate. When paired with cooperative mechanical and chemical devices such
as impulse turbines, electric generators, rocket motors and the like
these cooperating devices are able to capitalize on the high velocity
stream exhaust gases without otherwise requiring large volumetric flow
rates. The gas generator assembly 100 (as part of a micro-power unit
incorporating these other components) is thereby able to provide a
significant amount of power without requiring a large amount of fuel or
mixing of fuel with ambient air, other propellants and the like.

[0035] Referring now to FIGS. 3A and 3B, front and side views of the
porous reaction matrix 108 are shown. Referring first to FIG. 3A, the
plurality of matrix passages 202 are shown extending in and out of the
page. As previously described, in one example, the porous reaction matrix
108 is comprised of a matrix of members, plates or sheets, for instance,
a matrix grid 300 including a plurality of vertical and horizontal
members, plates and the like. In one example, the matrix grid 300
includes a plurality of mesh or porous members constructed with but not
limited to aluminum oxide. In one example, the preheater 208 is shown
extending over a plurality of the matrix passages 202.

[0036] Referring now to FIGS. 3A and 3B, as previously described the
catalyst 204 is provided along the matrix passages 202. As shown in FIG.
3A, the catalyst 204 is provided on the interior of each of the matrix
passages 202. For instance, the catalyst 204 is provided along the
interior of each of the matrix passages 202. Referring to FIG. 3B, as
shown the catalyst 204 is provided along the length of each of the matrix
passages 202. In one example, where the matrix grid 300 of the porous
reaction matrix 108 is a matrix mesh, for instance having an interstitial
spaces, the catalyst 204 (e.g., platinum) is positioned within the
interstitial spaces of the matrix grid 300 as shown in FIG. 3B. In one
example, the catalyst 204 is provided within the porous reaction matrix
108 from the matrix proximal portion 304 to the matrix distal portion
306. By providing the catalyst 204 in substantially all of the matrix
passages 202 the reaction chamber 106 ensures that the propellant
administered to the porous reaction matrix 108 from the injector 110
contacts the catalyst 204 no matter what matrix passage 202 the
propellant is delivered through.

[0037] As shown in FIGS. 2, 3A and 3B, the porous reaction matrix 108
includes a plurality of linear matrix passages 202. As previously
described, substantially all of the matrix passages 202 include the
catalyst 204 positioned therein. This ensures that the propellant 104
introduced into the reaction chamber 106 is catalyzed by the catalyst 204
no matter what matrix passage 202 the propellant is delivered through.
The linear channels of the porous reaction matrix 108 substantially
minimize stagnation points within the porous reaction matrix and minimize
any overheating of the matrix and the reaction chamber 106. Stated
another way, the linear matrix passages 202 provide a consistent and
reliable pathway for the propellant to move through the porous reaction
matrix 108 without generating heat concentrations (e.g., hot spots)
within the porous reaction matrix 108 that may otherwise damage the
matrix and possibly the reaction chamber 106. Further, the provision of a
plurality of linear matrix passages 202 substantially minimizes or
eliminates bottle necks or choke points within the porous reaction
matrix. The linear passages 202 thereby ensure that the flow of
propellant 104 through the porous reaction matrix is done in a rapid and
efficient manner without any full or partial stagnation within the porous
reaction matrix. The efficient delivery of exhaust gases from the porous
reaction matrix 108 to the discharge nozzle 112 is thereby substantially
ensured.

[0038] Although a porous reaction matrix 108 including linear matrix
passages 202 has been described herein, in other examples, the reaction
chamber 106 includes a reaction matrix composed of, but not limited to,
reticulated foam, honeycomb passages and the like. As with the porous
reaction matrix 108 described herein, the other options for the matrix
(e.g., a catalyst bed) include the catalyst such as platinum impregnated
with the other matrix types. For instance, with a reticulated foam,
platinum particles are administered throughout the reticulated foam to
ensure catalyzation of the propellant as the propellant is delivered
through the foam.

[0039] FIG. 4 shows one example of the propellant chamber 102 previously
shown in FIG. 1. The propellant chamber 102 includes a propellant chamber
body 400 configured to retain the propellant 104 therein under pressure,
for instance, the propellant chamber body 400 is constructed with
materials including but not limited metals, such as stainless steel,
aluminum, titanium and the like. The propellant chamber 102 is configured
to retain the propellant 104 at pressures of around 300 to 400 psi or
greater. In one example, the propellant chamber 102 includes a
deflectable inner bladder (shown with the inner line in FIG. 4) that
cooperates with the pressure generator 402 (described below) pressurize
and deliver the propellant into the reaction chamber 106. For instance,
the bladder includes a deflectable foil substrate including, but not
limited to, stainless steel, aluminum and the like around 1 to 2
millimeters thick. In another example, a PE, HDPE, PTFE liner or the like
is sprayed on the interior of the bladder to ensure the propellant 104
does not interact with the bladder material (though the bladder material
is already substantially inert).

[0040] As previously described, the propellant chamber 102 is configured
to contain an amine based propellant, such as hydroxyl ammonium nitrate
(HAN). The propellant 104 contained within the propellant chamber 102 of
the gas generator assembly 100 is a non-combustible propellant instead of
hazardous and unstable compounds that burn or are explosive in nature and
correspondingly have a relatively short shelf life. The amine based
propellant 104 contained within the propellant chamber 102 has a
substantially long shelf life, for instance, 20 years or longer.
Additionally, the amine based propellant 104 used with the gas chamber
assembly 100 and stored within the propellant chamber 102 does not need
ambient air for catalyzation. For instance, as previously described, the
porous reaction matrix 108 is configured to catalyze the amine based
propellant 104 by itself without additional fuels, ambient air and the
like. The controlled introduction of a fuel or ambient air to the
propellant along with the mechanical and control systems needed for the
controlled introduction of such materials is thereby avoided. The
propellant chamber 102 a pressurized chamber in communication with the
reaction chamber 106 through the propellant passage 114. Complex
compressors, fans, injectors and the like are thereby substantially
avoided.

[0041] In one example, the propellant 104 within the propellant chamber
102 is a dense propellant, for instance, an amine based propellant having
a specific gravity of 1.6 or greater (at least 60% heavier than liquid
water). The use of a dense propellant provides a small form factor (e.g.,
a small volume of the propellant includes a relatively high power output)
for the gas generator assembly 100. The dense propellant is gradually
atomized through the injector 110 and catalyzed within the porous
reaction matrix 108 shown in FIG. 1 over seconds or longer (depending on
the volume stored in the chamber 102) to provide a consistent stream of
propellant for operation of the gas generator assembly 100. Stated
another way, the amine based propellant 104 stored within the propellant
chamber 102 provides a significant amount of energy and power per unit
volume for the gas generator assembly 100 (and a micro power unit
including the same).

[0042] In one prophetic example, the gas generator assembly 100 (when
coupled with an impulse turbine assembly and electric generator, as
described below) including the propellant 104 has a power density of
around 882 Watts per kilogram and an energy density of around 88
Watt-hours per kilogram assuming sufficient volume and mass of the
propellant 104 is provided for around six minutes of operation. In one
example, the gas generator assembly 100 operable for around six minutes
is incorporated within a miniature UAV, such as the UAV 800 shown in FIG.
8. In contrast to the gas generator assembly 100 incorporated within a
micro power unit (e.g., see 501 and 701 below), a corresponding battery
power system configured to run for around six minutes may provide a power
density of around 30 to 600 Watts per kilogram and an energy density of
around 3 to 60 Watt hours per kilogram (for six minutes of operation).
The gas generator assembly 100 thereby provides more power per kilogram
than an equivalent battery system. Further, the gas generator assembly
100 loses weight throughout operation as the propellant 104 is catalyzed
and discharged. When the gas generator assembly 100 is incorporated
within a device, such as a UAV, the UAV uses the constant power
generation of the assembly 100 in combination with the gradually
decreasing weight of the assembly 100 to leverage greater operational
periods for the device. Alternatively the volume of propellant (and its
corresponding mass) is decreased while maintaining a similar operational
period to a heavier battery system.

[0043] As further shown in FIG. 4, in one example, the gas generator
assembly 100 includes a pressure generator 402 coupled with the
propellant chamber 102 through a pressurization passage 408. The pressure
generator 402 is configured to pressurize the propellant 104 within the
propellant chamber 102 and correspondingly deliver the propellant through
the propellant passage 114 to the reaction chamber 106 where it is
catalyzed by the porous reaction matrix 108. The pressure generator 402
includes, but is not limited to, a variety of pressure generator
mechanism, for instance, squibs, piston operated pressure generators,
chemically operated pressure generators and the like. In one example, the
pressure generator 402 is activated with an activator 404 coupled with
the pressure generator. For instance the activator 404 includes, in one
example, a lanyard 406 sized and shaped to initiate a reaction or
mechanical operation within the pressure generator 402 to deliver
pressure to the propellant chamber 102 and thereby deliver the propellant
104 through the propellant passage 114 to the reaction chamber 106.

[0044] In another example, the pressurization passage 408 includes a check
valve 410 sized and shaped to ensure the propellant 104 within the
propellant chamber 102 is unable to move into the pressure generator 402.
In one example, the check valve 410 includes but is not limited to a ball
check valve that readily permits the passage of pressurized fluid from
the pressure generator 402 through the pressurization passage 408 but
substantially prevents the opposed delivery of propellant 104 through the
pressurization passage 408 to the pressure generator 402.

[0045]FIG. 5 shows a schematic view of the gas generator assembly 100
previously described in FIG. 1 coupled with one example of an impulse
turbine assembly 504. The gas generator assembly 100 in combination with
the impulse turbine assembly 504 is one example of a micro power unit
501. As previously described, the gas generator assembly 100 includes a
propellant chamber 102 including a propellant 104 therein, such as an
amine based propellant, coupled with a reaction chamber 106 having a
porous reaction matrix 108. As shown in FIG. 5, the reaction chamber 106
includes a discharge nozzle 500 having a nozzle contour 502. Optionally,
the discharge nozzle 500 includes a rocket nozzle including a
corresponding nozzle contour 502 configured to direct exhaust gases
generated from the porous reaction matrix 108 at high velocity (e.g.,
supersonic) into the impulse turbine assembly 504. For instance, the
nozzle contour 502 accelerates exhaust gases and discharges the gases
from the reaction chamber 108 at velocities of around 5000 to 7000 feet
per second.

[0046] Referring again to FIG. 5, the impulse turbine assembly 504 is
shown coupled with the reaction chamber 106 and in fluid communication
through the discharge nozzle 500. The impulse turbine 504 assembly
includes a turbine housing 506 with a turbine rotor 508 therein. In one
example, the turbine rotor 508 is a radial impulse turbine including for
instance, a Pelton wheel. The turbine rotor 508 is rotatably movable
within the turbine housing 506 through coupling with a turbine shaft 510
extending through the turbine housing 506. As shown in FIG. 5, the
turbine rotor 508 includes a plurality of tangential cups 512 positioned
adjacent to the discharge nozzle 500. Stated another way, the discharge
nozzle 500 is configured to direct exhaust gases into tangential cups 512
and thereby rotate the turbine rotor 508 relative to the turbine housing
506. The turbine housing 506 further includes an exhaust discharge 516
configured to release exhaust gases from within the turbine housing 506
after the exhaust gases impinge upon the tangential cups 512 and transmit
kinetic energy into rotation of the turbine rotor 508 and the turbine
shaft 510.

[0047] Referring now to FIG. 6, the impulse turbine assembly 504 shown in
FIG. 5 is now shown from the top. The turbine rotor 508, for instance a
Pelton wheel, is rotatably positioned within the turbine housing 506. As
shown the turbine rotor 508 includes a plurality of tangential cups 512
positioned along the periphery of the turbine rotor 508. The plurality of
tangential cups 512 are positioned to ensure tangential impingement by
exhaust streams 602 delivered through the discharge nozzle 500 along the
periphery of the rotor 508. In one example, the plurality of tangential
cups 512 are positioned at a consistent radius 600 relative to a center
axis of the turbine shaft 510. For instance, the plurality of tangential
cups 512 are positioned at approximately 0.5 inches from the center axis
of the turbine shaft 510. With the plurality of tangential cups 512
positioned at radii of approximately 0.5 inches relative to the center
axis 604 of the turbine shaft 510 the impulse turbine assembly 504 has a
diameter of around 1 inch (or more with the housing 506 included).

[0048] As will be described in detail below, because the turbine rotor 508
relies on the impulse provided by the exhaust stream 602 from the
reaction chamber 106 a high velocity stream of exhaust gas generates
significant power generation with the impulse turbine assembly 504
without requiring high volumetric flow rate. Correspondingly, when the
exhaust stream 602 from the discharge nozzle 500 enters the impulse
turbine assembly 504 at supersonic velocity, for instance, 5000 to 7000
feet per second the corresponding rotational speed of the turbine rotor
508 generates significant power despite the miniaturized and compact form
factor of the micro power unit 501 including the gas generator assembly
100 and the impulse turbine assembly 504. Stated another way, the impulse
turbine assembly 504 relies on high velocity and low volumetric flow
rates to achieve significant power while other turbines such as radial
turbines rely on high volumetric flow rate with low velocity to generate
power. High volumetric flow rates correspondingly require large nozzles,
significant propellant storage and the like that facilitate the delivery
of large quantities of fluid into the turbine housing. Relatively large
axial turbines are required to generate power with the corresponding high
volumetric flow rates. Large turbines, large nozzles and greater
propellant storage (relative to the micro power unit 501) preclude the
miniaturization of turbine assemblies and thereby correspondingly
preclude the use of axial turbines in a miniaturized assembly such as the
gas generator assembly 100 described herein.

[0049] As previously described, the impulse turbine assembly 504 shown in
FIGS. 5 and 6 relies on a high velocity stream of exhaust gas 602
delivered from the discharge nozzle 500 and generated within the reaction
chamber 106 by catalyzing an amine based propellant 104 within the porous
reaction matrix 108. The impulse turbine assembly 504 relies principally
on the high velocity for power generation as opposed to the volumetric
flow rate of the stream of gas passing into the turbine housing 506 and
impinging upon the tangential cups 512. The force delivered by the
exhaust stream 602 to the tangential cups 512 rotates the turbine rotor
508 and correspondingly rotates the turbine shaft 510 to thereby generate
mechanical power for the micro power unit 501. In one example, the force
imposed by the exhaust stream 602 on one or more of the tangential cups
512 is represented by the following equation:

F=2ρQ(Vi-u)

[0050] In the equation F stands for the force on each of tangential cups
512 due to impinging of the exhaust stream 602 thereon. The Greek letter
ρ is the density of the exhaust stream 602 fluid. Q is the volumetric
flow rate of the exhaust gas into the turbine housing 506 while Vi
is the initial velocity of the exhaust stream 602 as it enters the
turbine housing 506. The quantity u is equivalent to the linear speed of
a point on the turbine rotor 508 at an identical radius to the tangential
cups 512. As shown in the force equation, the force delivered to the
turbine rotor 508 is at least partially generated according to the
volumetric flow rate of the exhaust stream 602 delivered into the impulse
turbine assembly 504. As will be described in further detail below there
is a stronger relationship between the velocity of the exhaust stream 602
relative to the power generated by the pulse turbine assembly 504. The
power generated by the impulse turbine assembly 504 is represented by the
following equation:

P=Fu

As previously described, the force equation is provided above and the
quantity u is equivalent to the linear speed of a point on the turbine
rotor 508 equal distance from the center of axis 604 of the turbine shaft
510 to one of the tangential cups 512 (e.g., equivalent to the radius of
the turbine rotor 508). The resulting equation for power is:

P=2ρQ(Vi-u)(u)

The derivative of the resulting equation is thereafter taken to find a
maximum power capable of being delivered by the impulse turbine assembly
504. The derivative of the equation is set equal to zero and u is solved
for. By setting the derivative equal to zero and solving for u the
velocity that achieves maximum power is determined (e.g., maximum power
occurs where the change in power over time is equal to zero at the peak
of the curve). By setting the derivative equal to zero and then solving
for u maximum power is generated with the impulse turbine assembly where
u is equal to:

u = V i 2 ##EQU00001##

[0051] As shown above, the velocity of the turbine rotor 508 is a function
of Vi, the exhaust stream 602 velocity. Returning to the previously
determined power equation for the impulse turbine assembly 504, when the
quantity u is exchanged for the velocity based value determined above
(Vi/2) the power equation is solved and is equivalent to:

P m ax = ρ Q V i 2 2 ##EQU00002##
P m ax = ρ A V i 3 2 ##EQU00002.2##

[0052] As shown above, when the volumetric flow rate Q is exchanged for
its components, the area of the discharge nozzle 500 and the incoming
velocity of the exhaust stream 602, the power equation shows that there
is a cubic relationship between the inlet velocity of the exhaust stream
602 (e.g., Vi) and the power. That is to say, by providing a high
velocity exhaust stream 602 to the impulse turbine assembly 504 the
velocity of the exhaust stream 602 has an exponential cubic relationship
to the power generated by the impulse turbine assembly 504. In contrast,
the area of the discharge nozzle 500 (one component of the volumetric
flow rate) has a simple multiplicative relationship to the power
generated by the impulse turbine assembly 504. Stated another way, by
maximizing the velocity of the exhaust stream 602 and minimizing the
volumetric flow rate through the discharge nozzle 500 significant power
is generated by the impulse turbine assembly 504 compared to
corresponding increases in the volumetric flow rate of the exhaust stream
602 and a corresponding decrease in the exhaust stream velocity.

[0053] FIG. 7 shows another example of the gas generator assembly 100
coupled with the impulse turbine assembly 504 previously shown in FIGS. 5
and 6 and an electric generator 700. The assembly of the gas generator
100, the impulse turbine assembly 504 and the electric generator 700 is
another example of a micro power unit 701 configured to generator one or
more of electrical and mechanical power. As previously described, the
exhaust stream 602 (see FIG. 6) is delivered to the impulse turbine
assembly 504 to turn the turbine rotor 508 and thereby rotate the turbine
shaft 510. In one example, the turbine shaft 510 is coupled, for instance
via a reduction drive, with mechanical components in another assembly
such as a miniature unmanned air vehicle. In the example shown in FIG. 7,
the turbine shaft 510 is coupled with the electric generator 700 (e.g.,
an alternator). As shown in FIG. 7, the electric generator 700 includes a
generator housing 702 having a stator 704 in the housing 702 surrounding
a generator rotor 706. Rotation of the turbine rotor 508 and turbine
shaft 510 is correspondingly transmitted to the generator rotor 706.
Rotation of the generator rotor 706 generates electricity in the stator
704.

[0054] As previously described, the exhaust stream 602 is delivered to the
impulse turbine assembly 504 at a high velocity, for instance, 5000 to
7000 feet per second. The power generated by the impulse turbine assembly
504 is equivalent to an exponent of the inlet velocity (Vi) of
discharge nozzle 500. The inlet velocity of discharge nozzle 500 has a
relationship to the rotational speed of the turbine shaft 510. For
instance, as previously described, when solving for the maximum power
capable of being generated by the impulse turbine assembly 504 the
velocity of a point on the turbine rotor 508 equivalent to radius of a
tangential cup 512 is equal to u and u is equal to the quantity
Vi/2. The velocity u divided by the radius of the tangential cups
512 provides the rotational speed of the turbine shaft 510. The generator
rotor 706 is rotated at this rotational speed (ω) and the electric
generator 700 correspondingly generates electricity according to the
speed of the generator rotor 706 rotation. Stated another way, the
greater the exhaust stream velocity 602 the greater the rotational speed
of the generator rotor 706. Accordingly, increasing the rotational speed
of the electric generator 700 generates increased electricity. As will be
described in further detail below, the electricity generated through the
electric generator 700 in combination with the impulse turbine assembly
504 (as the micro power unit 701) is used in one or more applications to
provide electricity for a flight control system in a miniature unmanned
air vehicle, rotation of a propeller for an unmanned air vehicle, for
charging of batteries and the like.

[0055]FIG. 8 shows one example of a miniaturized unmanned air vehicle
(UAV) including the gas generator assembly 100 as part of the micro power
unit 701 previously described herein. As shown in FIG. 8, the
miniaturized UAV 800 includes a UAV body 802 having a fuselage and wings
attached to the fuselage. As shown in FIG. 8, in one example, the
miniaturized UAV 800 includes a UAV propeller 804 rotatably coupled with
the UAV body 802. In one example, the UAV propeller 804 includes
adjustable blades 812. The adjustable blades 812 are operated with
attached blade actuators 814 to adjust the pitch of the adjustable blades
812 during operation of the miniaturized UAV 800.

[0056] Referring now to the schematic view of the micro power unit 701 and
the other components within the miniaturized UAV 800, the gas generator
assembly 100 includes a propellant chamber 102 including a propellant 104
therein. In one example, the propellant 104 includes a non-combustible
propellant such as an amine based propellant (e.g., hydroxyl ammonium
nitrate). In the example shown in FIG. 8, the propellant chamber 102 is
coupled with a pressure generator 402 configured to apply a pressure
through the propellant chamber 102 and thereby deliver the propellant 104
through the propellant passage 114 to a reaction chamber 106 including a
porous reaction matrix 108. As previously described, the porous reaction
matrix 108 includes a catalyst therein configured to catalyze the
propellant 104 and non-combustibly generate exhaust gases such as nitric
oxide, nitrous oxide, oxygen and the like. The exhaust gases are
delivered through the reaction chamber 106 to the impulse turbine
assembly 504 shown in FIG. 8. As previously described in one example, the
impulse turbine assembly 504 includes a Pelton wheel such as the turbine
rotor 508 shown in FIG. 5. The impulse turbine assembly 504 further
includes a turbine shaft 510 (see FIG. 5) coupled with the electric
generator 700. Rotation of the turbine rotor correspondingly rotates the
generator rotor 706 (see FIG. 7) and thereby generates electricity for
the miniaturized UAV 800.

[0057] In the example shown in FIG. 8, multiple components are shown
electrically coupled with the electric generator 700. For instance, the
electric generator 700 is shown coupled with a flight control system 808.
The generator 700 provides electrical power for the flight control system
808 and facilitates the control of the miniaturized UAV 800. In another
example, the miniaturized UAV 800 includes a battery 810 coupled with the
electric generator 700. During operation of the gas generator assembly
100, electricity generated by the electric generator 700 is optionally
stored within the battery 810 for future use by the miniaturized UAV 800.
In one example, the gas generator assembly 100 is operated over a
specified period of time and the electricity generated by the electrical
generator 700 is thereafter stored within the battery 810 for use during
the part of or for the entire operational stage of the miniaturized UAV
800. The inclusion of the gas generator assembly 100 facilitates the use
of a smaller battery 810 relative to larger batteries otherwise needed
for operation of the miniaturized UAV 800 that are configured to retain
their charge for extended shelf lives, for instance, 5 to 10 years.

[0058] In another example, the electric generator 700 is shown coupled
with a motor 806 mechanically coupled to the UAV propeller 804. As shown
in FIG. 8, the electric power generated through the electric generator
700 is transmitted to the motor 806 to rotate the UAV propeller 804 and
thereby provide motive power to the miniaturized UAV 800. In another
example, the flight control system 808 is operatively coupled with the
UAV propeller 804, for instance, the adjustable blades 812. The flight
control system 808 is configured to operate the blade actuators 814 and
thereby adjust the pitch of the blades 812. The flight control system 808
is able to adjust the power consumption of the UAV propeller 804 and
correspondingly adjust the overall speed of the miniaturized UAV 800. In
another example, the flight control system 808 is configured to
selectively deliver power to one or more of the UAV propeller 804 and the
battery 810 according to the operational needs of the miniaturized UAV
800 at discrete times during the operation of the UAV. For instance,
during operation of the gas generator assembly 100 the flight control
system 808 selectively delivers electrical energy from the electric
generator 700 to the UAV propeller 804 where the flight control system
808 determines that the UAV propeller 804 needs the entirety of the power
generated through the micro power unit 701 to achieve performance
parameters, for instance, maximum speed, thrust and the like. In another
example, where the flight control system 808 determines that the UAV
propeller 804 and the motor 806 do not at a particular time require all
of the power generated by the micro power unit 701 the flight control
system 808 diverts at least some of the electrical power generated by the
electric generator 700 to the battery 810 for storage and eventual use by
the UAV the motor 806 (and other systems of the UAV).

[0059] In another example, the flight control system 808 cooperates with
the micro power unit 701 (including the gas generator assembly 100) to
throttle the flow of propellant 104 from the propellant chamber 102 to
the reaction chamber 106 and the porous reaction matrix 108. By
throttling the flow of the propellant 104 to the reaction chamber 106
propellant is delivered and catalyze in a controlled and specified manner
to ensure appropriate power output is generated by the impulse turbine
assembly 504 coupled with the electric generator 700. For instance, in
one example, the flight control system is operatively coupled with the
propellant control valve 212 shown in FIG. 2. The propellant control
valve 212 includes a needle valve configured to precisely meter the
amount of propellant 104 delivered to the reaction chamber 106. By
metering the propellant 104 delivered to the porous matrix 108 the gas
generator assembly 100 in cooperation with the flight control system 808
is able to adjust the output of exhaust gases to the impulse turbine
assembly 504 and the corresponding rotational speed of the turbine rotor
508 and the generator rotor 706. The electric power output of the micro
power unit 701 including the turbine assembly 504 and the electric
generator 700 is thereby adjusted as needed according to the power needs
of the miniaturized UAV 800.

[0060] In still another example, the flight control system 808 is
operatively coupled with the blade actuators 814. The flight control
system 808 adjusts the aerodynamic characteristics of the UAV propeller
804 by adjusting the pitch of the adjustable blades 812. For instance, as
the gas generator assembly 100 operates by delivering the propellant 104
to the reaction chamber 106 a set amount of power is generated over a
unit time by the electric generator 700. The flight control system 808
adjusts the pitch of the adjustable blades 812 through operation of the
blade actuators 814 to correspondingly adjust the overall speed of the
miniaturized UAV 800.

[0061] The miniaturized UAV 800 including the micro power unit 701
(incorporating the gas generator assembly 100 and other components) as
shown in FIG. 8 provides significant operational advantages over
similarly designed UAVs including battery systems. For instance, the gas
generator assembly 100 includes a stable propellant 104, such as an amine
based propellant (e.g., hydroxyl ammonium nitrate), that has a long shelf
life and is substantially non-combustible. The use of a gas generator
assembly 100 including the propellant 104 thereby substantially
eliminates the hazards attendant with using a combustible propellant.
Additionally, the operation of the gas generator assembly 100, for
instance, during operation of the miniaturized UAV 800 decreases the mass
of the miniaturized UAV 800 over the span of time the propellant 104 is
delivered to the reaction chamber 106. For instance, as the propellant
104 is catalyzed within the porous reaction matrix 108 and the exhaust
gases are delivered to the impulse turbine assembly 504 the mass of the
propellant 104 gradually decreases. The overall mass of the miniaturized
UAV 800 thereby correspondingly decreases which facilitates a more
efficient operation of the miniaturized UAV as the electric motor 806 and
UAV propeller 804 operate to move a UAV body 802 having a gradually
decreasing weight.

[0062] Additionally, the gas generator assembly 100 in combination with
the impulse turbine assembly 504 and the electric generator 700 allows
for the electrical coupling of the gas generator assembly 100 with the
motor 806 of the UAV propeller 804. In another example, the impulse
turbine assembly 504 is mechanically coupled with the UAV propeller 804,
for instance with a reduction drive interposed therebetween. Further, as
described above, the flight control system 808 is able to selectively
throttle the power output of the gas generator assembly 100 through
operation of the blade actuators 814 coupled with the adjustable blades
812. By adjusting the pitch of the blades 812 the flight control system
808 is able to change the aerodynamic characteristics of the adjustable
blades 812 and thereby correspondingly alter the overall speed and
performance of the miniaturized UAV 800. In another example, and as
previously described, the flight control system 808 is configured to
throttle the flow of the propellant 104 to the reaction chamber 106, for
instance, with a propellant control valve 212 shown in FIG. 20. The
flight control system 808 in this configuration is able to control the
output of exhaust gases the from reaction chamber 106 to the impulse
assembly 504 and thereby correspondingly adjust and manage the electrical
power output of the electric generator 700. The electric generator 700
thereby produces an adjustable range of output power to the UAV propeller
804 and motor 806 to correspondingly adjust the overall speed and
performance of the miniaturized UAV 800.

[0063] Moreover, the micro power unit 701 included with the miniaturized
UAV 800 provides a complete power generating assembly that is fully
self-contained and does not require ambient air for operation. Instead
the non-combustible gas generator assembly 100 catalyzes the amine based
propellant 104 within the porous reaction matrix 108 and the catalyzation
generates the exhaust gases needed for operation of the impulse turbine
assembly 504. Further, the catalyzation of the propellant 104 within the
porous reaction matrix 108 generates exhaust gases at high velocity, for
instance 5000 to 7000 feet per second. The exhaust gases when delivered
through the discharge nozzle 500 impinge upon the tangential cups 512 of
the turbine rotor 508 to correspondingly rotate the turbine rotor 508 and
the attached generator rotor 706 to generate power. The micro power unit
701 is thereby able to operate in almost any environment (e.g., sea level
atmosphere, thin atmosphere environments, for instance the exosphere and
thermosphere and the like) and does not need additional compressors,
inlets for air and fuel and the like with the accompanying weight and
structure. Stated another way, the micro power unit 701 included in the
miniaturized UAV 800 operates as a closed system and thereby does not
need ambient air or other sources of fuel mixed with the propellant 104
for operation. Instead the gas generator assembly 100 by itself
non-combustibly generates exhaust gases and cooperates with the impulse
turbine assembly 504 and the electric generator 700 to correspondingly
generate power.

[0064] FIG. 9 shows one example of a battery charger 900 including the gas
generator assembly 100 previously described herein. As shown in FIG. 9,
the battery charger 900 further includes an impulse turbine assembly 504
and an electric generator 700 coupled with a gas generator assembly 100
(as the micro power unit 701). The battery charger 900 further includes a
charger housing 904 containing the gas generator assembly 100, the
impulse turbine assembly 504 and the electric generator 700. The charger
housing 904 further includes a battery receptacle 906 sized and shaped to
receive at least one battery therein. As shown in FIG. 9, two or more
terminals 908 are positioned within the battery receptacle 906 and
configured to make contact with at least one battery positioned within
the battery receptacle 906. As further shown in FIG. 9, in one example, a
regulator 902 (e.g., one or more of a voltage or a current regulator) is
interposed between the terminals 908 and the electric generator 700. The
regulator 902 is configured to condition electricity generated by the
electric generator 700 for recharging of one or more batteries positioned
within the battery receptacle 906. In one example, and further described
below, the regulator 902 is an adjustable regulator and configurable to
recharge one or more of a variety of different battery types. Optionally,
in another example, the regulator 902 includes a series of regulators
positioned within the charger housing 904 each of which is selectively
adjustable to supply a desired voltage or current to the terminals 908 of
the battery charger 900. For instance, where the battery charger 900
includes a plurality of battery receptacles 906, a plurality of
regulators 902 are used to selectively determine what voltage and current
combination delivered to each of the terminals 908.

[0065] As previously described, the gas generator assembly 100 operates by
delivering a propellant, such as the propellant 104, in the propellant
chamber 102 to a reaction chamber 106 including a porous reaction matrix
108. The propellant 104 includes, but is not limited to, hydroxyl
ammonium nitrate, a non-combustible propellant catalyzed by the catalyst
204 within the porous reaction matrix 108 to generate one or more exhaust
gases. The non-combustibly generated exhaust gases are delivered to the
impulse turbine assembly 504. As previously described in one example, the
exhaust gases are delivered to the impulse turbine assembly 504 at high
velocity, for instance, 5000 to 7000 feet per second (e.g., a supersonic
velocity). The exhaust gases impinge upon the tangential cups 512 of the
turbine rotor 508 and turn the turbine rotor and the associated turbine
shaft 510. Rotation of the turbine shaft correspondingly operates the
electric generator 700 and generates electricity for the battery charger
800.

[0066] As shown in FIG. 9, the battery charger 900 includes a regulator
902 configured to adjust the electrical output of the electric generator
700 according to the voltage and current specifications of any battery
configured for positioning within the battery receptacle 906. Optionally,
the regulator 902 is an adjustable regulator and the user is able to
select the voltage and current combination according to the battery to be
recharged within the battery receptacle 906. In yet another example, the
battery charger 900 includes a plurality of battery receptacles 906 sized
and shaped to receive a corresponding plurality and variety of batteries
therein. One or more regulators 902 are included in the battery charger
900. The one or more regulators 902 either include set regulator schemes
or variable regulator schemes according to the batteries positioned
within the multiple battery receptacles 906.

[0067] The battery charger 900 including the non-combusting gas generator
assembly 100 shown in FIG. 9 provides a number of advantages over battery
operated battery chargers. In one example, the battery charger 900
includes a stable long lasting power source with the propellant 104. The
propellant 104, for instance an amine based propellant, has a long shelf
life (e.g., 10 years or longer). Additionally, the amine based propellant
104 is stable and not subject to combustion or gradual decay while
stored. The battery charger 900 further allows a user to effectively
recharge batteries in the field. As described above, the battery charger
900 has a long shelf life with a stable non-hazardous propellant 104
therein. A user may carry the battery charger 900 in the field and
confidently use the battery charger 900 after months or even years in the
field or storage before actual use. The battery charger 900 is used to
recharge rechargeable batteries and provides a stable platform that the
user can rely on to confidently recharge the batteries while in the
field.

[0068] The micro power unit 701 included with the battery charger 900
provides a complete power generating assembly that is fully
self-contained and does not require ambient air for operation. Instead
the non-combustible gas generator assembly 100 catalyzes the amine based
propellant 104 within the porous reaction matrix 108 and the catalyzation
generates the exhaust gases needed for operation of the impulse turbine
assembly 504 and the electric generator 700 coupled with the turbine
assembly. The micro power unit 701 is thereby able to operate in almost
any environment (e.g., sea level atmosphere, thin atmosphere
environments, for instance the exosphere and thermosphere and the like)
and does not need additional compressors, inlets and the like (with
additional mechanical structure) to mix ambient air or other fuels with
the propellant. Stated another way, the micro power unit 701 included in
the battery charger 900 operates as a closed system and thereby does not
need ambient air or other sources of fuel mixed with the propellant 104
for operation. Instead the gas generator assembly 100 by itself
non-combustibly generates exhaust gases and cooperates with the impulse
turbine assembly 504 and the electric generator 700 to correspondingly
generate power.

[0069] FIG. 10 shows one example of a rocket motor 1000 coupled with the
non-combustible gas generator assembly 100 shown in FIG. 1. In the
example shown in FIG. 10, the rocket motor 1000 includes a rocket housing
1002 including a fuel 1004, such as a solid rocket propellant, positioned
along the rocket housing 1002. The rocket motor 1000 further includes an
initiator 1006 positioned within the rocket housing 1002. The initiator
1006 is configured to initiate a combustion reaction within the rocket
housing 1002, for instance, with exhaust gases generated by the reaction
chamber 106. The rocket motor 1000 further includes a rocket discharge
nozzle 1008 having a nozzle contour 1010. In one example, the rocket
discharge nozzle 1008 includes a nozzle contour 1010 configured to funnel
and direct exhaust gases from the rocket motor 1000 out of the rocket
housing 1002 according to a desired thrust and performance profile for
the rocket motor 1000.

[0070] As previously described, the non-combustible gas generator assembly
100 operates by delivering a propellant 104 from a propellant chamber 102
through an injector 110 into the reaction chamber 106. As previously
described, the propellant 104 in one example is a non-combustible amine
based propellant delivered to the porous reaction matrix 108 within the
reaction chamber 106. The introduction of the propellant 104 to the
porous reaction matrix 108 catalyzes the propellant 104 and generates a
exhaust gases. The exhaust gases are thereafter delivered through the
discharge nozzle 112 of the reaction chamber 106. In one example, the
exhaust gases include oxygen generated from the catalyzation of the
propellant 104. In another example, the propellant 104 includes, but is
not limited to, hydroxyl ammonium nitrate (HAN) while the catalyst within
the porous reaction matrix 108 includes the catalyst 204 (e.g.,
platinum). The catalyst 204 rapidly catalyzes the propellant 104 to
generate exhaust gases including, but not limited to, nitrous oxide,
nitric oxide and oxygen (e.g., O2). Where the reaction chamber 106
including the porous reaction matrix 108 and the propellant 104 generate
oxygen, the oxygen is delivered through the discharge nozzle 112 into the
rocket motor 1000. In one example, the oxygen exhaust delivered to the
rocket motor 1000 is delivered at high pressure and high temperature, for
instance, 1200° F. The high temperature exhaust gases including
oxygen are delivered into the rocket housing 1002 and mixed with the fuel
1004. The initiator 1006 thereafter operates the rocket motor by
initiating a combustion reaction between the fuel 1004 mixed with oxygen.
The resulting combustion reaction generates rocket exhaust gases that are
directed through the rocket discharge nozzle 1008. The rocket exhaust
gases directed through the rocket discharge nozzle 1008 are accelerated
according to the nozzle contour 1010 and thereby generate a desired
thrust profile.

[0071] The assembly of the rocket motor 1000 with the non-combustible gas
generator assembly 100 thereby provides a complete rocket assembly
including oxygen generated by the gas generator assembly 100 and routed
to the rocket housing 1002 for combustion with the fuel 1004. The rocket
motor 1000 thereby includes a fully self-contained system that does not
require ambient air for operation. Instead the non-combustible gas
generator assembly 100 catalyzes the amine based propellant 104 within
the porous reaction matrix 108 and the catalyzation generates the oxygen
needed for operation of the rocket motor 1000. Further, the catalyzation
of the propellant 104 within the porous reaction matrix 108 generates
exhaust gases at relatively high temperatures, for instance, 1200°
F. The exhaust gases when delivered through the discharge nozzle 112 act
to preheat the rocket motor 1000 and thereby assist in initiation of the
fuel 1004 in combination with the initiator 1006. The rocket motor 1000
is thereby able to operate in almost any environment (e.g., sea level
atmosphere, thin atmosphere environments, for instance the exosphere and
thermosphere as well as vacuum environments and the like). Stated another
way, the rocket motor 1000 operates as a closed system and thereby does
not need ambient air or other sources of fuel for mixture with the fuel
1004 for operation. Instead the gas generator assembly 100 provides the
oxygen needed for the fuel 1004 to initiate a combustion reaction within
the rocket housing 1002 to operate the rocket motor 1000 and generate
exhaust gases deliverable through the rocket discharge nozzle 1008.

[0072] FIG. 11 shows one example of a method 1100 for using a gas
generator such as the non-combustible gas generator 100 shown in FIG. 1.
Reference is made in description of the method 1100 to various features
and elements previously described herein. Where appropriate, reference
numbers are provided in the description of the method 1100. Reference
numbers are not intended to be limiting. Instead, any reference to a
particular element or feature is intended to include references to all
similar components described herein as well as their equivalents. At
1102, the method 1100 includes delivering an amine based propellant
(e.g., hydroxyl ammonium nitrate) to a gas generator, such as a reaction
chamber 106 shown in FIG. 1. As previously described above in one
example, the propellant 104 is delivered to the reaction chamber 106 from
a propellant chamber 102. For instance, the propellant 104 is pressurized
through the introduction of a pressurized fluid (e.g., gas) generated by
a pressure generator 402, for instance shown in FIG. 4.

[0073] At 1102, the amine based propellant 104 is directed through a
porous reaction matrix 108. The porous reaction matrix 108 includes a
catalyzing agent such as the catalyst 104 (e.g., platinum) shown in FIG.
2. At 1106, the amine based propellant 104 is non-combustibly catalyzed
into one or more pressurized exhaust gases with the porous reaction
matrix 108 having the catalyst 204 disposed therein. In one example,
non-combustibly catalyzing the amine based propellant 104 includes
non-combustibly catalyzing the propellant 104 in a closed system. For
instance, the porous reaction matrix 108 and the amine based propellant
104 are isolated from ambient air and other sources of fuel. As shown for
instance in FIG. 1, the gas chamber assembly 100 is a substantially
closed system wherein the propellant 104 is delivered, for instance
through an injector 110, to the porous reaction matrix 108 for
catalyzation by the catalyst 204 disposed within the porous reaction
matrix 108. The closed catalyzation within the porous reaction matrix 108
generates exhaust gases including, but not limited to, nitrous oxide,
nitric oxide and oxygen.

[0074] At 1108, the exhaust gases generated by the catalyzation of the
propellant 104 within the porous reaction matrix 108 are accelerated and
discharged through a discharge nozzle such as the discharge nozzle 112
shown in FIG. 1. In one example, the exhaust gases are accelerated and
discharged from the discharge nozzle 500 (see FIG. 5) at supersonic
velocity (e.g., 5000 to 7000 feet per second).

[0075] Several options for the method 1100 follow. In one example, the
method 1100 includes preheating the porous reaction matrix 108 with a
preheating substrate such as the preheater assembly 206 shown in FIG. 2.
In one example, the preheating assembly 206 preheats the porous reaction
matrix 108 including the catalyst 204 therein to a specified threshold
temperature configured to ensure the complete catalyzation of the
propellant 104 introduced into the reaction chamber 108 delivered through
the porous reaction matrix. For instance, the preheating assembly 206
preheats the porous reaction matrix 108 to a temperature of approximately
260 degrees Celsius to 1100 degrees Celsius. In one example, preheating
of the porous reaction matrix 108 includes delivering a preheating pulse
of the amine based propellant 104 to the preheating substrate such as the
preheater 208 shown in FIG. 2. In one example, the preheater 208 includes
a hypergolic substance disposed within a substrate coupled across the
porous reaction matrix 108. The method 1100 further includes reacting the
amine based propellant 104 with the hypergolic substance to produce heat.
The heat generated by the preheater 208 is conducted to the porous
reaction matrix 108 coupled with the preheater 208. In still another
example, the method 1100 includes measuring the temperature of the porous
reaction matrix 108 against the temperature threshold (for instance, a
threshold of approximately 260 to 1100 degrees Celsius). The method 1100
further includes delivering a catalyzing stream of the amine based
propellant 104 to the porous reaction matrix 108 if the measured
temperature meets or exceeds the temperature threshold. As shown in FIG.
2A, in one example, the preheating assembly 206 includes a temperature
sensor 210 coupled with the porous reaction matrix 108. The temperature
sensor 210 is coupled with a propellant control valve 212 that meters the
flow of propellant 104 into the reaction chamber 106. The previously
described preheating pulse is delivered through the propellant control
valve 212 where the propellant control valve is partially closed and
thereby configured to deliver a small stream of the propellant 104 to the
porous reaction matrix 108 and the preheater 208 coupled over the porous
reaction matrix. After operation of the preheater 208, the temperature
sensor 210 monitors the temperature of the porous reaction matrix 108 and
opens the propellant control valve 212 when the temperature of the porous
reaction matrix 108 meets or exceeds the threshold temperature needed for
a desired catalyzation of the propellant 104 within the porous reaction
matrix 108.

[0076] In another example, accelerating and discharging the one or more
pressurized gases for instance, the exhaust gases generated through
catalyzation of the propellant 104 by the porous reaction matrix 108
includes discharging the one or more pressurized gases against an impulse
turbine, for instance, a turbine rotor 508 within a turbine housing 506
of a turbine assembly 504 shown in FIG. 5. In one example, the turbine
rotor 508 includes a plurality of tangential cups 512 where the turbine
rotor 508 is configured as a Pelton wheel (e.g., an impulse turbine). As
previously described, the exhaust gases discharged through the discharge
nozzle 500 shown in FIG. 5 are delivered in a tangential manner to the
tangential cups 512 to rotate the turbine rotor 508 and thereby
correspondingly rotate the turbine shaft 510. Rotation of the turbine
shaft 510 is configured to generate mechanical power through the rotation
of the shaft as well as electrical power where the turbine shaft 510 is
coupled with an electric generator, such as the generator 700 shown in
FIG. 7. In one example, the method 1100 includes throttling power
generated from the impulse turbine (e.g., mechanical power or electrical
power in the case of generator 700) through throttling delivery of the
amine based propellant 104 to the reaction chamber 106. For instance, the
propellant control valve 212 shown in FIG. 2 is operated according to,
for instance, a flight control system, such as the system 808 shown in
FIG. 8 within a miniaturized UAV 800, to adjust one or more of the
mechanical or electrical power generated by the gas generator assembly
100 in combination with one or more of the impulse turbine assembly 504
and the electric generator 700.

[0077] In yet another example, the method 1100 includes discharging the
one or more pressurized gases such as the exhaust gases generated by the
catalyzation of the propellant 104 by the porous reaction matrix 108
through a rocket motor 1000. Referring to FIG. 10, the rocket motor 1000
includes a fuel 1004 such as a solid fuel configured to mix with the
exhaust gases including for instance, oxygen. The rocket motor 1000
further includes an initiator 1006 to initiate a combustion reaction
between the oxygen and the fuel 1004 and generate thrust by delivering
rocket exhaust gas through a rocket discharge nozzle 1080.

CONCLUSION

[0078] In accordance with some embodiments, the non-combusting gas
generator described herein provides an assembly configured to generate a
source of exhaust gas for use in a micro power unit. The non-combusting
gas generator includes a propellant chamber housing a dense
non-combustible propellant. The propellant is introduced to a reaction
chamber including a porous reaction matrix having a catalyst suspended in
the porous reaction matrix. The catalyst catalyzes the propellant within
the reaction matrix and generates exhaust gases for use by one or more
mechanical and electrical systems. Combining the gas generator with power
generation systems including, but not limited to, turbine assemblies and
electric generators forms a micro power unit configured to generate
significant power as a closed compact system.

[0079] The gas generator assembly introduces and consumes the propellant
(e.g., an amine based propellant, such as hydroxyl ammonium nitrate)
within a closed system. The gas generator assembly does not require
ambient air or supplemental fuels mixed with the propellant to catalyze
or react the propellant and produce the exhaust gases. Stated another
way, the gas generator assembly does not combust the propellant (e.g.,
with ambient air). Instead, the propellant is catalyzed and consumed
within a closed system and the exhaust gases are reliably produced in
substantially any environment (e.g., vacuum, high and low oxygen
environments and the like).

[0080] Further, the propellant used with the gas generator assembly is a
stable non-combustible propellant. In one example, the propellant is an
amine based propellant, such as hydroxyl ammonium nitrate. As described
herein, the amine based propellant is catalyzed within the porous
reaction matrix including a catalyst to produce exhaust gases. The
non-combusting propellant is not combustible by itself and is
correspondingly stable. Accordingly, the propellant may be stored for
months or years with no significant performance degradation.
Additionally, because the propellant is non-combustible it is a minimal
hazard to transport and store relative to other combustible propellants.
Further still, in the case of the amine based propellant described herein
the propellant is dense (e.g., with a specific gravity greater than
around 1.6) and a small amount of the propellant generates a significant
amount of exhaust gas. The gas generator assembly including the amine
based propellant thereby has a small form factor. The gas generator
assembly is readily incorporated as a small light weight component of
devices including, but not limited to, miniaturized UAVs and other field
equipment while still delivering significant power to the devices over a
specified operational lifespan.

[0081] Moreover, the exhaust gas generated by the non-combusting gas
generator is directed through a discharge nozzle for use by one or more
components. In one example, the exhaust gas is accelerated to supersonic
velocity (e.g., 5000 to 7000 feet per second) and impinges against one or
more tangential cups of an impulse turbine. The impulse turbine relies
heavily on the velocity of the exhaust gas (as opposed to volumetric flow
rate used in axial turbines) to rotate and correspondingly generate
power. The discharge nozzle minimizes the volumetric flow rate and
thereby conserves the propellant for extended performance of the gas
generator assembly and operation of the impulse turbine. As described
herein the impulse turbine assembly is coupled with one or more of an
electric generator to generate electric power or a reduction drive
coupled with a propulsion device (e.g., a propeller) of a miniaturized
UAV. Furthermore, during operation of the gas generator the propellant is
gradually consumed and exhausted from the UAV. The weight of the UAV
gradually decreases over its operation and thereby extends the
operational lifespan.

[0082] In the foregoing description, the subject matter has been described
with reference to specific exemplary examples. However, it will be
appreciated that various modifications and changes may be made without
departing from the scope of the present subject matter as set forth
herein. The description and figures are to be regarded in an illustrative
manner, rather than a restrictive one and all such modifications are
intended to be included within the scope of the present subject matter.
Accordingly, the scope of the subject matter should be determined by the
generic examples described herein and their legal equivalents rather than
by merely the specific examples described above. For example, the steps
recited in any method or process example may be executed in any order and
are not limited to the explicit order presented in the specific examples.
Additionally, the components and/or elements recited in any apparatus
example may be assembled or otherwise operationally configured in a
variety of permutations to produce substantially the same result as the
present subject matter and are accordingly not limited to the specific
configuration recited in the specific examples.

[0083] Benefits, other advantages and solutions to problems have been
described above with regard to particular examples; however, any benefit,
advantage, solution to problems or any element that may cause any
particular benefit, advantage or solution to occur or to become more
pronounced are not to be construed as critical, required or essential
features or components.

[0084] As used herein, the terms "comprises", "comprising", or any
variation thereof, are intended to reference a non-exclusive inclusion,
such that a process, method, article, composition or apparatus that
comprises a list of elements does not include only those elements
recited, but may also include other elements not expressly listed or
inherent to such process, method, article, composition or apparatus.
Other combinations and/or modifications of the above-described
structures, arrangements, applications, proportions, elements, materials
or components used in the practice of the present subject matter, in
addition to those not specifically recited, may be varied or otherwise
particularly adapted to specific environments, manufacturing
specifications, design parameters or other operating requirements without
departing from the general principles of the same.

[0085] The present subject matter has been described above with reference
to examples. However, changes and modifications may be made to the
examples without departing from the scope of the present subject matter.
These and other changes or modifications are intended to be included
within the scope of the present subject matter, as expressed in the
following claims.

[0086] It is to be understood that the above description is intended to be
illustrative, and not restrictive. Many other examples will be apparent
to those of skill in the art upon reading and understanding the above
description. It should be noted that examples discussed in different
portions of the description or referred to in different drawings can be
combined to form additional examples of the present application. The
scope of the subject matter should, therefore, be determined with
reference to the appended claims, along with the full scope of
equivalents to which such claims are entitled.

Patent applications by Jeremy C. Danforth, Tucson, AZ US

Patent applications by Richard D. Loehr, Tucson, AZ US

Patent applications by Raytheon Company

Patent applications in class SPECIFIC DRIVE OR TRANSMISSION MEANS

Patent applications in all subclasses SPECIFIC DRIVE OR TRANSMISSION MEANS